Method for performing chemical reactions, particularly in underground storage cavities



METHOD FOR PERFORMING CHEMI CALQREAC TIONS, PARTICULARLY STORAGE CAVITIES Allen D. Garrison, La Jolla, Calif., assignor to Texaco Inc., a corporation of Delaware No Drawing. Filed Nov. 13, 1956, Ser. No. 621,528 11 Claims. (Cl. 260-604) IN UNDERGROUND The present invention relates to a novel method for liquids of different specific gravities which are contained in a vessel, and is particularly concerned with carrying out chemical reactions in an underground storage cavern having a residual body of brine or other water solution therein which is kept from contact with the chemical reactants by the novel means of a barrier layer interposed between the water solution and the reactants.

It is a feasible to perform many types of chemical reactions in huge underground storage caverans such as may be washed out in salt and clay beds. Such caverns are particularly suited for producing changes in hydrocarbons by slow reactions carried out over a long period of time at relatively low temperatures. Examples of chemical reactions which can be so performed, and to which my invention is applicable, are the isomerization of normal paraflins, cycloparaflins, and normal olefins to the corresponding iso compounds; alkylation of an olefinhaving a relatively small number of carbon atoms u with an isoparaffin' to form hydrocarbons having a relatively large number of carbon atoms and a high octane number; the conversion of straight chain hydrocarbons to the corresponding cyclo compounds; and the polymerization of olefins. Others are hydrogenation, dehydrogenation, and oxo (reaction of CO and H with unsaturated hydrocarbons to produce oxygenated compounds), all of which require high pressures such as can be developed easily and safely underground. Still others are the bromination, chlorination, and nitration of saturated hydrocarbons to make them reactive; and the fermentation of carbohydrates.

In accordance with the invention of the above application, such chemical reactions are safely performed over a long period of time at low cost by introducing the reactants into a cavern located deep within the earth (for example, 1,000-2,000 feet down), contacting the reactants with a catalyst effective to promote the desired chemical reaction, and maintaining the reactants in contact with the catalyst in the underground cavern for a period of time sufiicient to effect the chemical reaction in a substantial amount.

It is generally unnecessary to' add heat by fuel combustion because the temperature existing within the earth, for example IOU-200 F. at feasible cavern depths, is sufficient for the chemical reaction over a long period of time, such as six months to two years. However, some additional heat can be added by circulating a stream of the reactants through a conventional heat exchanger at the surface before introduction into the cavern; or even after introduction a continuous circulation of all or a a portion of the reactants through such a heat exchanger t thereto at least one organic radical.

"2,939,884 Patented June 7, 1960 forming my method advantageously is formed within a natural salt formation such as a dome or bed by first drilling a hole from the surface down into the salt formation, inserting conduits for fluid flow, and circulating water down into the formation to dissolve the salt which is then carried up to the surface as brine. For example, a cavern about 20-40 feet in diameter and about 1,000- 2,000 feet in length can be formed within a salt dome located about 1,000 feet below the surface of the earth. Caverns having capacities of over 4 million gallons have been formed in this way, but both smaller and larger sizes are feasible.

A cavern similarly may be washed out of a clay bed by using a deflocculating liquid solution. Reference is made to Patent 2,803,432, issued August 20, 1957, for such a procedure.

The completed cavern is full of brine or other solution which should be removed to provide space for the chemical reactants. This can be done by forcing the lighter reactants down on the top of the brine which is thus forced up through a pipe to the surface. It is almost impossible to effect complete removal of brine so that there usually is a shallow pool of brine in the bottom of a cavern. This brine may deleteriously affect the chemical reaction by polluting the chemical reactants and by poisoning the catalyst.

In accordance with the present invention, the deleterious effect of the brine or other water solution in a cavern is counteracted by floating on its surface a barrier layer of a material which is insoluble in, and inert or unreactive with, both the brine and the chemical reactants, and

which has a specific gravity intermediate such two liquids.

cific gravity less than 1.0. Other suitable barrier mate trials are flexible plastic or resinous materials dissolved in suitable solvents, for example synthetic butyl or buna rubber dissolved ina water soluble solvent such as ace tone or methyl ethyl ketone, or carboxy methyl cellulose in the same solvents. The solvent eventually dissolves in the aqueous pool and a flexible non liquid impervious coating remains. Other suitable materials are methacrylate polymers such as lauryl and octyl methacrylates alone or mixed, in an oil base constituting, for example, 60% of the mixture by weight.

Typical liquid silicone polymers include condensation products of organo-silicon oxides such as those condensation products containing a plurality of silicon atoms linked through oxygen atoms, each silicon atom having attached Such compounds have come to be called silicones by reason of their containing the so-called silicone radical, i.e.,

tion or condensation of organosilicols, the latter includt ing mono, di-, and trisilicols as well as various mixtures thereof.

Such compounds may be representedl by the following formula:

R R s r-0 -s't-R Preferably R isa singleforganicradical of lovv' -molecu larweight sirch'as methyl, ethyl andshortchain alkyl- Liquid compounds having organic radicals of groups. I l 7 h 4 high :molecular weight such-{as phenyls or compounds containing organic radicals-ofboth high and low molecular weights can beused.

A- preferred" compound is the alkyl silicon" dimethyl" silicon polymer; having the following formula:

in which. n is 1.or:more.. In most cases itis believed 1004000 cs: viscosities being preferred: Specific gr-avities 25/25 C. range from 0.761 to 0.9.73for the 0.65 to.1,000.cs. range.

While the principles ofthe present-invention maybeappliedto any type of chemicahreaction performed in avessel containing .apool of liquid, such as brine, which must be kept from contact with the reactants and cata' lysts, itis particularly applicable toisomerization, alkylation, cyclo conversion; polymerization,hydrogenation, and oxygenation.

In anisomeiization reaction, relatively short chain light paraffin hydrocarbons such as butanes, and also the corresponding olefins, are converted to'thecorrespondin'g iso compounds. The barrier material is then introduced on the top of the brine to forrna layer of suitable thickness, ,such as one inch to six inches thick. The liquid normal hydrocarbon, suchlas butane, is then-introduced into :thestorage cavern on top-of the barrier layer and the pool of brine. A suitable catalyst is added to'thc hydrocarbon before or after introduction. Among such catalysts are aluminum chloride, hydrogen fluoride, boron. trifluoride," and. aluminum bromide. The reactants are then'retained in the cavern for a sufiicient time to efiectsubstantial conversion to the desired iso compounds, this time sometimes being as long as sixmonths or a year.:

In alkylation,i.relatively short chain isoparaffin hydrocarbons. are. reacted with relatively short. chain olefins' to produce. longer. chain saturated isoparaffin hydrocarbons.

catalystsuchasboron trifiuorideor aboron trifluoridehydrogen trifiuoride mixture. The'reaction mixture is then allowed .to remain in the'cavern until the reaction hasoccurred. If desired, the. alkylation can proceed with For exampleisobutane and butylene can be ap-. plied on the top of the silicon and brine is a cavern in a ratio of approximately 5:1 by Weight, and provided with or Diese1 fuel is introduced into a cavern on top of a silicone'layerand'treated "with hydrogen in the presence of a catalyst such as cobaltmolybdate, nickel-tungsten sulfide, or nickel.

In oxygenation (0x0) a cobalt carbonyl catalyst is dissolved in an olefin sucli as 'ethylene or propylene which is;introduced intora cavern on top of" a["' Sil'i'COI 1 laye'ri Gaseous hydrogen and carbon monoxide in ratios of l l on top of a silicone layer with a catalyst such as hydrated phosphoric acid, or with-Ia silica-alumina base impregnated with the oxides group ,V of'the periodic table.

In hydrogenation a material such as crude oil, naphtha,

by volume are then pumped dowii'into thecavcrnto'elfect reaction.

Elxfiiiz'pl' A 1 storage cavern roughlyQO feet in diameter :and 500 feet long located 1,000 feet below the surce, within a salt dome, contains a-"p6o'lof residual brine three feet deep. Into this cavern there is introduced 605 pounds of liquid dirnethyl' -silicone"- of F? 1 00 cs.'--kinematic viscosity to pro, vide a'barrier layer 'thieein'ch'es thick floating on the top 1 of the brine pool. Thebrin'e has a specificgravity of 1.197 20/4 C. -and"=the '100 cs. silicone has a specific" gravity of--O;968 so' that it floats readily on the'top of the brine:

The t-est of-thecavity-is then substantially filled with liquid butane' having a density of 0.601 at 0 C. so that it floats upon the silicone layer and is effectively separated from c'orit'act'w'ith the brine. Hydrogen trifluoride=boron-trifiuoride' catalyst is then introduced into the butane 1 and distributed uniformly "therein;-

After six" months" storage in the cavern the upper layer is' removed by pumping in brine todisplace the-f upper layer while-the" floating silicone barrieralso rises": to maintain separation of 'the phases. The isobutane' is then separated' from the'nonnal butane'by' distillation It is "evident that the principles of 'the present inven tion"are'primarilyapplicable to conducting 'chem'icalr 1 actions 'in've's'sels' such as huge underground storage cav" erns as'described above.- However, it'sh'ould'be clearl understoodthat they alsoapply in any situation'wher'e it is" I necessar'ytdpreventcontact between-two inwrnpatius, liquids of different specific gravities contained in a vess" of any type, whether on a laboratory scale or in a-pla rit size reactor. Obviously, many modifications -and"variations"of the invention, as'he'reinb'efore set forth, may be made without 7 departing fr'omthe spirit and scope'lthereof,'andftlier fore only such limitations should be imposed asflare in dicated in the appended claims. I

I claim:

1. A method for conducting'a catalyticchemical reaction in anunderground storage caVernlQcated "in art i earth-formation and containing 'a pool of liquid corn: prising .water, said'me'thod comprising maintaining in" said cavern on the top of said pool a'fioa ting 'layer'of* an inert barrier material having a specific gravity "less than said-first named liquid, and maintaining on th'e'top ofisaid layer of inert barrier material a reactant liq'uid' chemical having a catalyst associated therewith and'ha ving a specific gravity less' than said inert 'barn'er material, said layer spacing said liquids vertically from unsanother. r g

2. A method in accordance with claim 1 wherein said reactant liquid 'chemical isa normal 'hydrocarbonfand said catalyst is an" isomerizationcatalyst.

3. A method'inaccordance with claim 1 wherein'saidi reactant liquid is a cycloparafiin'hydrocarbon, and said' catalyst is an isomerizntion catalyst.

4. A method in accordance withclairn'l, wherein said' reactant liquid is a paraffin hydrocarbon, and said'catalyst is effective to='co'nv'ert saidparaffin hydrocarbon to the corresponding' cycloparafiin.

5. A'method-in accordance'witholaim l wherein said reactant liquid is a mixture of 'an isoparafiin hydrocarbon and an olefin hydrocarbon, and said catalyst is an" alliylation catalyst? 6. A method in accordance witlrclain'i-dwheieih sai 1 reactant liquid is an olefin hydrocarbon, and said catalyst is a polymerization catalyst.

7. A method in accordance with claim 1 wherein said reactant liquid is an olefin and said catalyst is an oxygenation catalyst, said method also comprising introducing hydrogen and carbon monoxide into contact with said olefin in said cavern.

8. A method in accordance with claim 1 wherein said earth formation is salt, said pool is brine, and said inert barrier material is a liquid silicone.

9. A method. in accordance with claim 1 wherein said floating layer of an inert barrier material is also a liquid.

10. A method in accordance with claim 1 wherein said earth formation is salt and said pool is brine.

11. A method for conducting a catalytic chemical reaction in an underground storage cavern located in an earth formation and containing a pool of liquid comprising water, said method comprising first introducing and maintaining in said cavern on the top of said pool a floating layer of an inert barrier material having a specific References Cited in the file of this patent UNITED STATES PATENTS 2,104,488 Kennedy et a1. Jan. 4, 1938 2,265,962 Bent et a1 Dec. 9, 1941 2,330,079 Owen Sept. 21, 1943 2,382,471 Frey Aug. 14, 1945 2,383,123 Gorin Aug. 21', 1945 2,423,674 Agren July 8, 1947 2,677,666 Daugherty May 4, 1954 2,722,277 Crawford Nov. 1, 1955 2,729,549 Reman et a1. Jan. 3, 1956 1 FOREIGN PATENTS 131,131 Australia Jan. 24, 1949 

1. A METHOD FOR CONDUCTING A CATALYTIC CHEMICAL REACTION IN A UNDERGROUND STORAGE CAVERN LOCATED IN AN EARTH FORMATION AND CONTAINING A POOL OF LIQUID COMPRISING WATER, SAID METHOD COMPRISING MAINTAINING IN SAID CAVERN ON THE TOP OF SAID POOL A FLOATING LAYER OF AN INERT BARRIER MATERIAL HAVING A SPECIFIC GRAVITY LESS THAN SAID FIRST NAMED LIQUID, AND MAINTAINING ON THE TOP OF SAID LAYER OF INERT BARRIER MATERIAL A REACTANT LIQUID CHECMICAL HAVING A CATALYST ASSOCIATED THEREWITH AND HAVING A SPECFIC GRAVITY LESS THAN SAID INERT BARRIER MATERIAL, SAID LAYER SPACING SAID LIQUIDS VERTICALLY FROM ONE ANOTHER. 